Abstract: A method and apparatus used to compensate for thermal displacement and to correct a positional error caused by the thermally induced displacement of a spindle positioned in response to a numerical control system. The amount of thermally induced displacement of the spindle, at a predetermined point in time after application of electric power to the machine tool, is stored in a memory. When the spindle is to be positioned in response to numerical control data, the commanded amount of spindle movement is compensated by using the amount of thermally induced displacement stored in the memory, and the spindle is then positioned on the basis of the compensated commanded amount of movement.

Abstract: A numerical controller, which is equipped to perform sequence control of a heavy-current circuit for a machine tool, has an interface line to which both an NC system operator panel and an additional operator panel are attached. The additional operator panel is dedicated to the function of entering, debugging, and confirming the sequence control program. The interface line is connected via a buffer circuit to a main bus in the numerical controller. When the sequence program is debugged, only the additional operator is enabled and key information from the additional operator is read into a main processor in the numerical controller to carry out debugging of the sequence control program under the control of a debugging execution program. When the NC system operator panel is used, the additional operator panel is disabled, thus switching between the operator panels.

Abstract: An industrial robot having a robot hand attached to a robot arm, a rotary motion unit supporting therein the robot arm, a vertical motion unit on which the rotary motion unit is disposed, and a vertical hollow structure extending through the vertical and rotary motion units and defining therein a vertically extending wiring and piping space.

Abstract: The direction of pick feed is determined by a feed-direction signal produced based on the result of decision by a phase decision circuit and the direction of pick feed inputted from an input unit, and the pick feed is effected by a contour trace. In the case of tracing a hemispherical model, the pick feed can be achieved in a plane parallel to the X-Y plane. The feed-direction signal indicates whether the direction of tangential velocity is to be +90.degree. or -90.degree. with respect to the normal direction. A velocity arithmetic circuit inverts the polarity of its output, a tangential-direction velocity signal, depending on the binary value of the feed-direction signal. Motors are driven by the outputs from amplifiers selected by a gate circuit, by which, in the case of tracing the hemispherical model, the pick feed plane is made to correspond to that in the case of a contour trace, wherein the pick feed can be effected in a plane parallel to the X-Y plane.

Abstract: During machining of a workpiece, the feed of the wire electrode and the discharge for the machining are stopped and the wire electrode is moved in a direction perpendicular to the machining path until it contacts the wall of the workpiece. The size of the spark gap is then detected from the position where the wire electrode contacts the workpiece. A desired offset value is calculated from the detected size of the spark gap and the known wire diameter. The machining path is corrected so that the center of the wire electrode lies at a position offset by the desired offset value relative to a desired profile.

Abstract: An industrial robot, having a manipulative robot hand for mounted on a vertically movable portion thereof moved by a vertical drive, provided with a load reducing pneumatic cylinder for applying a constant upward force to the vertically movable portion during the vertical movement of the portion and an air storage tank or tanks directly connected to the pneumatic cylinder for continuously supplying air under a desired fixed pressure. The upward force contributes to reducing a load applied to the vertical drive. The air storage tank or tanks contributes to ensuring mechanical rigidity of the industrial robot.

Abstract: A device for cooling a reversible motor comprising: a plurality of blade-type cooling fins (17) attached to the protrusion (13b) of a rotary shaft (13) which protrusion is protruded into a cooling chamber (5) formed on the outside of a motor case (10); an exhaust blower (25) provided on the outer side of the cooling chamber (5) in the axial direction to expel the cooling air, and; a fixed rectifying vane (29), consisting of a plurality of radially arrayed guide vanes (29a), provided in the exhaust space (28) between the blade-type cooling fins (17) and the exhaust blower. In the cooling device, the cooling air stream, moving in a spiral manner, passes through the blade-type cooling fins (17), is rectified in the axial direction via the fixed rectifying vane (29) and is expelled by the exhaust blower (25), when the motor runs in both the forward and the reverse directions.

Abstract: A circuit for controlling a D.C. electromagnetic brake, in which a series circuit consisting of a solenoid 35 for the electromagnetic brake and a transistor 52 for controlling the current that flows into the solenoid is connected to a D.C. power source 8 and wherein a varistor 4 is connected in parallel between the emitter and the collector of the transistor 52 which controls current that flows into the solenoid, in order to clamp the counter electromotive force that generates across the emitter and the collector of the transistor when the current flowing through the solenoid is interrupted.

Abstract: Disclosed is an industrial robot having a function for controlling a current of a motor for driving, which comprises a circuit (41) for summing a plurality of input signals to which input signals of speed command, speed feedback, current command and current feedback are supplied, a switching circuit (23) for selectively switching the input of speed command to the inputs of current command and current feedback by a switching command signal and an operational amplifier (38) to which the switched signal is supplied. In this industrial robot, the position control is switched over to the current control by a switching command signal from a robot control device (22), and by the position control, an article to be held is shifted to a predetermined position and by the current control, driving electric motors (Mr, M.theta.

Abstract: A method and apparatus for circular interpolation on the basis of a given arc center O, arc starting point P.sub.s and arc end point P.sub.e. In a case where the given arc end point P.sub.e does not lie on an arc of center O passing through the given arc starting point P.sub.s, a new center O.sub.N of an arc passing through the points P.sub.s, P.sub.e is computed, and circular interpolation is performed on the basis of the computed center O.sub.N, the given starting point P.sub.s and the given end point P.sub.e.

Abstract: An AC motor control method and apparatus therefor, for controlling an AC motor 11 by holding the excitation current I.sub.0 of the AC motor 11 constant and varying primary current I.sub.1 in accordance with a speed deviation .DELTA.n. Stored previously in a memory device 18 are a torque T-slip frequency .omega..sub.s characteristic, a slip frequency .omega..sub.s -primary current vector I.sub.1 characteristic, and a slip frequency .omega..sub.s and phase .phi..sub.1 characteristic which take secondary leakage reactance into account. Slip frequency .omega..sub.s, primary current vector I.sub.1 and phase .phi..sub.1 are read out of the memory device in accordance with the torque command T obtained from the speed deviation .DELTA.n, whereby three-phase current commands i.sub.u, i.sub.v, i.sub.w are produced. Accordingly, torque irregularity is suppressed and an excellent response obtained.

Abstract: In a system which performs tracer control by calculating the direction and velocity of tracing using signals from a tracer head tracing the model surface, there are provided an input unit for entering data defining the tracing operation, a memory for storing the data and a processor for reading out the data from the memory to control respective parts of a control device. Of the data defining the tracing operation, stored in the memory, data concerning the reference displacement of the tracer head is read out by the processor to change the reference displacement for each profile modeling operation, thereby automatically performing repetitive tracing.

Abstract: A speed control circuit and position control circuit are connected to a spindle drive motor in a machine tool or the like in order to drive the spindle at a predetermined speed and stop the spindle at a predetermined angular position. When an orientation command is issued while the spindle is being rotated at the predetermined speed by a speed control loop, a speed command signal from a speed command circuit is interrupted, the speed reduced to zero, and an initially set voltage is then employed as a speed command to rotate the spindle by a predetermined amount. Next, a integral value of the actual spindle speed is employed as the speed command to further rotate the spindle by a predetermined amount. When this has been accomplished, a constant bias voltage of a low level replaces the speed command, thereby to rotate the spindle still further by a predetermined amount until a specified portion of the spindle approaches extremely close to the predetermined angular position.

Abstract: A discharging circuit for a power source device with a rectifier circuit used in an power source for driving a motor in which when the alternating current power source is turned off and the load is electrically separated, the voltage of a time constant selection circuit (22, 23) falls rapidly, the voltage across a diode (25) rises, a Schmitt circuit (24) is activated, the circuit consisted of a transistor (27) and a resistor (26) is conducted, and a smoothing capacitor (28) is discharged, and hence the heat generation at the resistor is decreased and the concern over unsafety due to delayed discharge of the capacitor is eliminated.

Abstract: A method and system for rewriting data in a non-volatile memory in which the rewriting of one access unit of stored data is executed by erase and write cycles, the stored data being protected in the event of an interruption in electric power. In rewriting into second data the first data which is stored in a data storage area of the non-volatile memory, either the first or the second data is stored in a save area of the non-volatile memory, after which the first data in the data storage area is erased, followed by the writing of the second data in the data storage region to complete the rewrite operation.

Abstract: A method of adjusting for a shift of the position of a stylus tip and a deviation of the zero point of a displacement detector which are caused by an exchange of a stylus of a tracer head. The shift of the position of the stylus tip and the deviation of the zero point of the displacement detector are electrically or mechanically read out as displacement. In accordance with the displacement, the tracer head assembly is moved relative to a machine frame to adjust the tip of the stylus to its reference position.

Abstract: A portable bubble memory apparatus having a bubble memory cassette for accommodating a bubble memory element, and a portable cassette adapter provided with a cassette holder for loading and unloading the bubble memory cassette, the portable cassette adapter housing a control circuit and peripheral circuitry for the bubble memory element. A signal generator generates a signal to indicate whether the bubble memory cassette has been loaded at the correct position within the cassette holder. If the bubble memory cassette is displaced from the correct position, the generated signal causes the exchange of information between the bubble memory cassette and an external unit to cease.

Abstract: In a transmission system employing a plurality of parallel lines for transmitting serial digital signals, means are provided in each line for detecting and disconnecting any line on which transmission is interrupted comprising a converter for producing two signals of opposite polarity, a receiver for reconverting the signals connected to the converter by a pair of transmission lines, an exclusive OR gate connected to the pair of transmission lines for providing an output when normal signals of opposite polarity are present, and a switch comprising an AND gate converted to the receiver and to the exclusive OR gate which disconnects the receiver when no output is received from the exclusive OR gate. The received signals from each line are combined through a common OR gate.

Abstract: A direct current motor comprising: a yoke; an armature; a plurality of main magnetic poles equidistantly spaced around the inner circumference of the yoke, and each of which has a wide portion and a narrow portion, the air-gap between the armature and the main magnetic poles being narrow at the center and ends of the wide portion, and at the center of the narrow portion, and being wide at the intermediate of the wide portion, and at the ends of the narrow portion, and a plurality of interpoles, such as E-shaped interpoles, which are disposed at positions located between the adjacent narrow portions of the main magnetic poles.

Abstract: A wire-cut, electric discharge machining method in which a wire is inserted into a machining start hole made in a workpiece to start electric discharge machining from the machining start hole, a bushing of a conductive material is pressed into a hole made in the workpiece to provide the machining start hole.